Flexible shaft



April 8, 1952 F. A. MONAHAN FLEXIBLE SHAFT 3 Sheets-Sheet 1 Filed Dec. 1, 1949 INVENTQR.

mi mi April 8, 1952 F. A. MONAHAN FLEXIBLE SHAFT 3 Sheets-Sheet 2 Filed Dec. 1, 1949 INVENTOR. :9. a. 7mm

3 Sheets-Sheet 5 F. A. MONAHAN FLEXIBLE SHAFT April 8, 1952 Filed Dec. 1, 1949 INVENTOR.

Patented Apr. 8, 1952 FLEXIBLE SHAFT Fred A. Monahan, Detroit, Mich., assignor to Morris Farm Machinery Company, Detroit,

Mich.

Application December 1, 1949, Serial No. 130,530

This application discloses a flexible shaft for coupling a driving shaft to a driven shaft for transmission of rotary motion even though the axis of rotation is arranged to be shifted or curved laterally, typical of the lateral shifting that takes place in the class of devices known as flexible shafts or couplings.

The flexible shaft or coupling hereof includes an outer cover in the form of a flexible hose or tube surrounding an intermediate assembly in the form of an articulated tube of end connected rings in turn surrounding and journalling an inner or driving assembly of end connected driving links. For rotary coupling the driving and driven shafts and the end links of the inner assembly are connected, thus coupling the driving and driven shafts through the flexible shaft or coupling hereof for transmission of rotary forces.

It is one aim and object of the present invention to provide a novel form of inner assembly, which essentially comprises alternate'male and female driving links, loosely connected to permit angular relative shifting.

It is another aim and object of the present invention to provide a construction wherein the outer cover is not subjected to stresses due to friction drag between the inner assembly and the articulated tube in which the inner assembly is journalled and to which the outer cover is secured.

It is a further aim and object of the present invention so to form the outer tube that it functions not as a means for confining heat within the coupling, but as an effective means for dissipating heat generated within the coupling while still retaining its function of flexing and confining the lubricant within the coupling.

To accomplish the latter aims and objects, I have provided so-called frictionless bearings, such as balls or rollers or other friction-reducing means, between the inner assembly and the articulated tube whereby substantially all friction drag between the inner assembly and the articulated tube is eliminated and have formed the outer cover in the form of a corrugated, thin, heat conducting tube, such as a tube of copper or aluminum or the like, having its ends fixed to the articulated tube. Hence, there are no forces created, to be resisted by the outer cover which, when made in the form of the corrugated copper tube above described, is not capable of resisting suc'h forces.

An embodiment of the invention, developed in accordance with the foregoing aims and objects, is disclosed in the accompanying drawings and is described in the following specification.

In these drawings:

Fig. 1 i a longitudinal elevation view of one embodiment.

1 Claim. (01. 642) Fig. 2 is a fragmentary longitudinal cutaway view, as if on line 2-2 of Fig. 1.

Figs. 3 and 4 are transverse section views 0 lines 3-3 and 44 of Fig. 2.

Fig. 5 is an exploded perspective view of the driving links.

Fig. 5 is an enlarged longitudinal sectional view at the driving end of the flexible shaft.

Fig. 7 is an exploded view of two ringswhich are joined to form part of'the articulated tube. The drawings show a flexible shaft or coupling including an intermediate assembly 2, an inner assembly 3 (Fig. 5), andan outer cover 4.

The intermediate assembly The inner assembly 3 includes a plurality of end connected, alternately spaced, double male links 20 and double female links 2|. Each male link 20 is in the form of a short rod having squared or non-circular male enlargements 22,,

and adjacent ones of these are disposed in adjacent ends of thesquared or non-circular bores 23 of the links 2|, these having outside grooves 24 receiving the journalling balls or bearings I3 and thus being journalled in the main rings ll] of the articulated tube. Enlargements 22 are loosely disposed in bores 23 and are crowned as shown to permit relative angular displacement of links 20-2|. End teats 25 on links 20 and snap rings 26 in grooves 21 of links 2| form end thrust limitations or stops for links 20. Oil channels 28 on enlargements 22 permit and encourage longitudinal and rotary flow of oil in the articulated tube.

The outer cover and the end constructions The outer cover 4 is in the form of a corrugated or bellows type sheet metal tube 50 characterized by its circular ribs or corrugations and protected by a braided metal sheath 5| and having its ends integrally secured to the ends of the articulated tube.

The outer cover may be of any suitable heat conducting material, copper or aluminum being preferred. It functions to provide a flexible envelope for the lubricant inside it, while dissipating heat within it.

to end fittings or rings 60-6I surrounding'end' Each adapter 62-63 has its adapters 62-63. inner end 64 formed like a female driving link 23, with a square internal bore 65 for an end 22 of a male driving link 20, and such end 64 is journalled, through bearing balls 66, in an end ring 61 simulating a bearing ring I 0, and connected by pins [-16 to a bearing ring I 1. Each adapter 62-63 has its outer end 10 internally formed for driving connection with a driving or driven shaft, i. e., it is splined as at 11', or formed with a keyway, as at 12, with set screw holes 13 for locking set screws also being shown, whereby the driving and driven shafts may be longitudinally locked to the adapters. Oil seals 15 seal the adapters 62-63 to the rings Gil-6| of the outer cover 4 in which the adapters are journalled.

Each adapter has shoulders 16-11 for endwise engagement by an end or a shoulder of the driving or driven shafts, if the set screws do not hold or are not being used, whereby end compressive forces from either the driving or driven shaft cannot be transmitted to the inner drive assembly 3 but are rather absorbed by the articulated tube 2. End separation forces obviously cannot be transmitted to the inner assembly 3. If such forces exist, they also will be absorbed by the articulated tube 2.

End ring 66 has taped holes 18-19 for lubri-' cating and pressure relief fittings and its inner end 64 contains an oil pressure maintaining piston and spring arrangement 80.

'llhe drive The drive from the splined driving shaft to the keyed driven shaft is established through the splined adapter 62 (10-1l-64), links 20 and 2!,

and the keyway adapter 63 (64-10-12), and all 4 articulated tube or intermediate assembly 2 by the bearing balls 66 against relative endwise motion, it can be seen that end thrust to and from the driving and driven shafts is absorbed by the assembly 2 and is not transmitted through the drive or inner assembly 3.

For convenience of manufacture and assembly, as well as for promoting efficiency of performance, parts I 0 and 2 Lin pairs, and parts 62-61, and parts 63-61, also in pairs, are formed as subassemblies, with each pair III-2|, 62-61, 63-61 of the parts being interlocked against relative longitudinal motion by the bearing balls l3 and 66, seated in the complementary grooves I224, etc. of the pairs of parts.

Now having described the flexible coupling means herein disclosed, reference should-be had etc the claim which follows.

I claim: In a flexible coupling or shaft, a plurality of swivelly and end to end connected outer races angularly shiftable with respect to one another, a plurality of inner races therein, friction reducing bearings between the inner and outer races whereby the outer races journal the inner races, the inner races having non-circular inner bore portions, male driving links connecting the inner races and comprising short rods having non-circular male ends disposed in the non-circular bore portions of the inner races, with each inner race receiving adjacent ends of two links and with each link disposed in two adjacent inner races, the male ends of the links being loosely disposed in the inner bore portions of the inner races to permit relative angular displacement of the inner races and the male links. the outer races being interconnected by means of swivel rings inside which are the short rods.

I FRED A. MONAHAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Gay Aug. 18, 1903 De Correvont Nov. 9, 1920 Granville Aug. 4, 1931 j FOREIGN PATENTS Country Date England Oct. 10, 1912 Number Sibley Dec. 3, 1889 

